Carbon nanotubes are allotropes of carbon with a nanostructure that can have a length-to-diameter ratio of up to 28,000,000:1. These cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science, as well as potential uses in architectural fields. They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat.
One known method of producing carbon nanotubes is laser ablation. In the laser ablation process, a pulsed laser vaporizes a target in a high-temperature reactor while an inert gas is bled into the chamber. The target is a composite of a carbon source (usually graphite or an amorphous carbon powder) and metal catalyst particles (typically a cobalt and nickel mixture). Nanotubes develop on the cooler surfaces of the reactor as the vaporized carbon condenses. A water-cooled surface may be included in the system to collect the nanotubes.
Known art involves pressing and binding targets with a carbon cement (e.g. Dylon GC, Dylon Industries, Inc.). Dylan carbon cement has graphite/carbon blend particles that are approximately 200 micron sized bound with a low surface area lamp black and phenolic resin in furfuryl alcohol as a binder. The large particle size inherent in Dylon produces regions of uncatalyzed target that are large compared to the laser spot. Other known techniques involve pressing conventional graphite or carbon powders that result in structurally weak products. Previous target recipes use metal powders that are sold by chemical supply stores, and are specifically selected for their high purity (typically 99.9%) and not for their particle size.